Systems can be used to cut or mark a workpiece that has a thickness and is composed of a type of material such as steel, metal, aluminum, among others. Generally, a cutting operation is cutting completely through the workpiece and a marking operation is marking a surface of the workpiece. Such systems can include, laser cutting systems, waterjet cutting systems, automated cutting systems, plasma cutting systems, among others.
Laser cutting systems use a laser to cut materials. A laser cutting system directing a high-power laser at the workpiece to be cut or marked. The workpiece can be either melted, burned, or vaporized away, and is blown away by a jet of gas, leaving a high-quality surface and clean edge. For instance, laser cutting systems can be used to cut or mark flat-sheet material as well as structural and piping materials.
Waterject cutting systems uses high-pressure jet of water, or a mixture of water and an abrasive substance to cut or mark a workpiece. Waterjet cutting systems can cut or mark materials such as metal or granite (using a mixture of water and an abrasive substance) and rubber or wood (using water without an abrasive substance).
Plasma cutting tools used to cut or otherwise operate on a workpiece typically comprise a gas nozzle with an electrode therein. Generally, plasma tools direct gas through a nozzle toward the workpiece, with some or all the gas ionized in a plasma arc between the electrode and the workpiece. The arc is used to cut, mark or otherwise operate on the workpiece.
In most tools, a pilot arc is first established between the electrode and the nozzle. Then, the pilot arc is transferred from the nozzle to the workpiece for cutting and/or other operations. For example, some tools use contact-based starting, with the electrode and nozzle initially in contact with one another. While current is passing through the electrode and nozzle, the electrode and nozzle are moved apart to create a gap. A spark across the gap initiates the pilot arc in a successful starting operation. While others use high voltage (either high frequency AC or a DC pulse) to break down the gap where the electrode and nozzle are fixed with respect to one another.
Cutting and/or marking systems are automated or semi-automated and what is needed is an improved technique to improve cycle times, quality (cut face surface finish and bevel), and accuracy of the cutting or marking operation.